Comparative study of infrared nanosecond laser surface paint removal for carbon fiber reinforced polymer and glass fiber reinforced polymer

Carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) are widely used in aerospace applications due to their excellent properties. Green and efficient laser cleaning technology has a broad development prospect in the paint removal treatment of aerospace composites. However, the lack of theoretical analysis and guidance has prevented the industrial application of laser paint removal technology. An infrared nanosecond laser is used to clean the paint layer on the surface of CFRP and GFRP, and the best paint removal process parameters are explored. Surface micromorphology and 3D morphology of CFRP and GFRP after cleaning are observed to reveal the cleaning quality. The FTIR spectrum is used to verify the cleanliness of the paint layer. In addition, the contact angle and bonding force are tested, and the experimental results show that the surface wettability of both surfaces is enhanced after cleaning, and the paint adhesion of both surfaces is improved after repainting. Temperature monitoring, acoustic signal monitoring and high-speed photography monitoring are used to monitor the two cleaning processes respectively. The temperature, amplitude intensity, and plasma size of the two in the cleaning process are compared and analyzed. Based on the monitoring results, it is found that the cleaning mechanism of fiber-reinforced composites includes thermal ablation, vibration effect and plasma impact effect.